Biform Resolidification and Amorphous Phases in a Laser and Electron Beam Processed Tantalum-Iridium Alloy

摘要

A 50 at. % Ta-Ir alloy has been surface melted by a CW CO sub 2 laser and, in a separate study, by a CW electron beam. Metallographic and transmission electron microscopic analysis has revealed both a microcrystalline region and amorphous regions in the resolidified layers. Evidence has been found by TEM that amorphous regions of two distinct compositions exist in the laser-irradiated case. A two-dimensional finite element heat flow analysis has been used to estimate cooling rate and resolidification velocities. (ERA citation 09:035808)